7841921 has 2 divisors, whose sum is σ = 7841922. Its totient is φ = 7841920.

The previous prime is 7841893. The next prime is 7841929. The reversal of 7841921 is 1291487.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4456321 + 3385600 = 2111^2 + 1840^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-7841921 is a prime.

It is a super-2 number, since 2×7841921² = 122991449940482, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (7841929) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3920960 + 3920961.

It is an arithmetic number, because the mean of its divisors is an integer number (3920961).

Almost surely, 2^7841921 is an apocalyptic number.

It is an amenable number.

7841921 is a deficient number, since it is larger than the sum of its proper divisors (1).

7841921 is an equidigital number, since it uses as much as digits as its factorization.

7841921 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4032, while the sum is 32.

The square root of 7841921 is about 2800.3430147037. The cubic root of 7841921 is about 198.6739017504.

The spelling of 7841921 in words is "seven million, eight hundred forty-one thousand, nine hundred twenty-one".